The increased sensibility on environmental problems and the growing price of oil have focused research during the past few years on reducing energy consumption. As for the automotive field, research is devoted to increase vehicle efficiency and reduce pollutant emissions. In that context, the increasing interest on vehicle electrification (HEV, PHEV, EV) brought manufacturers and researchers to invest significant resources in the research and development of advanced energy storage systems, particularly in advanced battery systems. The Book focuses on lithium-ion technology because of its superior characteristics suitable for electric vehicles. Even if batteries are so common in day-by-day life, thanks to portable electronic systems, the need to use them in EVs and HEVs has underlined new issues with respect to the ones already solved for mobile electronic systems. Characterization, modeling, State-of-Charge etimations and disequalization phoenomena are the subjects of this Book.